Through the cooperation of investigators in a number of institutions (Acute Leukemia Group B), chemotherapeutic regimens are planned and executed for the treatment of acute leukemia, lymphomas, multiple myeloma, childhood solid tumors and a few adult solid tumors. New agents are used in clinical trials and agents known to be effective are tried in new dosage schedules or in combination with other drugs. Intensive therapeutic regimens are used early in the disease in an attempt to cure or significantly prolong life. In advanced disease resistant to agents known to be effective, new agents are tried to determine their therapeutic efficacy in various malignant diseases, having first acquired knowledge of their effectiveness in various animal screens and understanding of the toxicology.